AVS 46th International Symposium
    Organic Electronic Materials Topical Conference Monday Sessions
       Session OE+EM+FP-MoA

Paper OE+EM+FP-MoA8
Liquid Crystal Imprinting: A New Method for Preparing Uniformly Oriented Thin Films

Monday, October 25, 1999, 4:20 pm, Room 616/617

Session: Transport and Nanostructures in Organic Films
Presenter: D.L. Patrick, Western Washington University
Correspondent: Click to Email
A new synthetic strategy is presented for preparing nanostructured thin films possessing macroscopically-uniform organization. The method is based on the use of a thermotropic nematic liquid crystal (LC) solvent, which serves a growth medium for deposition of material onto a suitable substrate. Application of a magnetic field results in the formation of an oriented film whose directionality can be controlled externally. The method has been used to prepare several organic monolayer systems in which the orientation of the films' molecular constituents is highly controlled. We show that orientational order at the solid-fluid interface originates during film nucleation, and that the alignment mechanism is based on anisotropic anchoring interactions between surface adsorbates and the LC solvent. Details of the relationship between molecular-scale surface structure and bulk LC ordering were studied by combining scanning tunneling microscopy and polarized optical measurements of uniformly oriented cells. LC fluids exhibit anisotropic anchoring interactions with most crystalline surfaces, indicating that the method may be applicable to the synthesis of films and layered materials using a wide range of molecular and supramolecular building blocks.